+% @float FLOATTYPE,LABEL,LOC ... @end float for displayed figures, tables,
+% etc. We don't actually implement floating yet, we always include the
+% float "here". But it seemed the best name for the future.
+%
+\envparseargdef\float{\eatcommaspace\eatcommaspace\dofloat#1, , ,\finish}
+
+% There may be a space before second and/or third parameter; delete it.
+\def\eatcommaspace#1, {#1,}
+
+% #1 is the optional FLOATTYPE, the text label for this float, typically
+% "Figure", "Table", "Example", etc. Can't contain commas. If omitted,
+% this float will not be numbered and cannot be referred to.
+%
+% #2 is the optional xref label. Also must be present for the float to
+% be referable.
+%
+% #3 is the optional positioning argument; for now, it is ignored. It
+% will somehow specify the positions allowed to float to (here, top, bottom).
+%
+% We keep a separate counter for each FLOATTYPE, which we reset at each
+% chapter-level command.
+\let\resetallfloatnos=\empty
+%
+\def\dofloat#1,#2,#3,#4\finish{%
+ \let\thiscaption=\empty
+ \let\thisshortcaption=\empty
+ %
+ % don't lose footnotes inside @float.
+ %
+ % BEWARE: when the floats start float, we have to issue warning whenever an
+ % insert appears inside a float which could possibly float. --kasal, 26may04
+ %
+ \startsavinginserts
+ %
+ % We can't be used inside a paragraph.
+ \par
+ %
+ \vtop\bgroup
+ \def\floattype{#1}%
+ \def\floatlabel{#2}%
+ \def\floatloc{#3}% we do nothing with this yet.
+ %
+ \ifx\floattype\empty
+ \let\safefloattype=\empty
+ \else
+ {%
+ % the floattype might have accents or other special characters,
+ % but we need to use it in a control sequence name.
+ \indexnofonts
+ \turnoffactive
+ \xdef\safefloattype{\floattype}%
+ }%
+ \fi
+ %
+ % If label is given but no type, we handle that as the empty type.
+ \ifx\floatlabel\empty \else
+ % We want each FLOATTYPE to be numbered separately (Figure 1,
+ % Table 1, Figure 2, ...). (And if no label, no number.)
+ %
+ \expandafter\getfloatno\csname\safefloattype floatno\endcsname
+ \global\advance\floatno by 1
+ %
+ {%
+ % This magic value for \thissection is output by \setref as the
+ % XREFLABEL-title value. \xrefX uses it to distinguish float
+ % labels (which have a completely different output format) from
+ % node and anchor labels. And \xrdef uses it to construct the
+ % lists of floats.
+ %
+ \edef\thissection{\floatmagic=\safefloattype}%
+ \setref{\floatlabel}{Yfloat}%
+ }%
+ \fi
+ %
+ % start with \parskip glue, I guess.
+ \vskip\parskip
+ %
+ % Don't suppress indentation if a float happens to start a section.
+ \restorefirstparagraphindent
+}
+
+% we have these possibilities:
+% @float Foo,lbl & @caption{Cap}: Foo 1.1: Cap
+% @float Foo,lbl & no caption: Foo 1.1
+% @float Foo & @caption{Cap}: Foo: Cap
+% @float Foo & no caption: Foo
+% @float ,lbl & Caption{Cap}: 1.1: Cap
+% @float ,lbl & no caption: 1.1
+% @float & @caption{Cap}: Cap
+% @float & no caption:
+%
+\def\Efloat{%
+ \let\floatident = \empty
+ %
+ % In all cases, if we have a float type, it comes first.
+ \ifx\floattype\empty \else \def\floatident{\floattype}\fi
+ %
+ % If we have an xref label, the number comes next.
+ \ifx\floatlabel\empty \else
+ \ifx\floattype\empty \else % if also had float type, need tie first.
+ \appendtomacro\floatident{\tie}%
+ \fi
+ % the number.
+ \appendtomacro\floatident{\chaplevelprefix\the\floatno}%
+ \fi
+ %
+ % Start the printed caption with what we've constructed in
+ % \floatident, but keep it separate; we need \floatident again.
+ \let\captionline = \floatident
+ %
+ \ifx\thiscaption\empty \else
+ \ifx\floatident\empty \else
+ \appendtomacro\captionline{: }% had ident, so need a colon between
+ \fi
+ %
+ % caption text.
+ \appendtomacro\captionline{\scanexp\thiscaption}%
+ \fi
+ %
+ % If we have anything to print, print it, with space before.
+ % Eventually this needs to become an \insert.
+ \ifx\captionline\empty \else
+ \vskip.5\parskip
+ \captionline
+ %
+ % Space below caption.
+ \vskip\parskip
+ \fi
+ %
+ % If have an xref label, write the list of floats info. Do this
+ % after the caption, to avoid chance of it being a breakpoint.
+ \ifx\floatlabel\empty \else
+ % Write the text that goes in the lof to the aux file as
+ % \floatlabel-lof. Besides \floatident, we include the short
+ % caption if specified, else the full caption if specified, else nothing.
+ {%
+ \atdummies \turnoffactive \otherbackslash
+ % since we read the caption text in the macro world, where ^^M
+ % is turned into a normal character, we have to scan it back, so
+ % we don't write the literal three characters "^^M" into the aux file.
+ \scanexp{%
+ \xdef\noexpand\gtemp{%
+ \ifx\thisshortcaption\empty
+ \thiscaption
+ \else
+ \thisshortcaption
+ \fi
+ }%
+ }%
+ \immediate\write\auxfile{@xrdef{\floatlabel-lof}{\floatident
+ \ifx\gtemp\empty \else : \gtemp \fi}}%
+ }%
+ \fi
+ \egroup % end of \vtop
+ %
+ % place the captured inserts
+ %
+ % BEWARE: when the floats start float, we have to issue warning whenever an
+ % insert appears inside a float which could possibly float. --kasal, 26may04
+ %
+ \checkinserts
+}
+
+% Append the tokens #2 to the definition of macro #1, not expanding either.
+%
+\def\appendtomacro#1#2{%
+ \expandafter\def\expandafter#1\expandafter{#1#2}%
+}
+
+% @caption, @shortcaption
+%
+\def\caption{\docaption\thiscaption}
+\def\shortcaption{\docaption\thisshortcaption}
+\def\docaption{\checkenv\float \bgroup\scanargctxt\defcaption}
+\def\defcaption#1#2{\egroup \def#1{#2}}
+
+% The parameter is the control sequence identifying the counter we are
+% going to use. Create it if it doesn't exist and assign it to \floatno.
+\def\getfloatno#1{%
+ \ifx#1\relax
+ % Haven't seen this figure type before.
+ \csname newcount\endcsname #1%
+ %
+ % Remember to reset this floatno at the next chap.
+ \expandafter\gdef\expandafter\resetallfloatnos
+ \expandafter{\resetallfloatnos #1=0 }%
+ \fi
+ \let\floatno#1%
+}
+
+% \setref calls this to get the XREFLABEL-snt value. We want an @xref
+% to the FLOATLABEL to expand to "Figure 3.1". We call \setref when we
+% first read the @float command.
+%
+\def\Yfloat{\floattype@tie \chaplevelprefix\the\floatno}%
+
+% Magic string used for the XREFLABEL-title value, so \xrefX can
+% distinguish floats from other xref types.
+\def\floatmagic{!!float!!}
+
+% #1 is the control sequence we are passed; we expand into a conditional
+% which is true if #1 represents a float ref. That is, the magic
+% \thissection value which we \setref above.
+%
+\def\iffloat#1{\expandafter\doiffloat#1==\finish}
+%
+% #1 is (maybe) the \floatmagic string. If so, #2 will be the
+% (safe) float type for this float. We set \iffloattype to #2.
+%
+\def\doiffloat#1=#2=#3\finish{%
+ \def\temp{#1}%
+ \def\iffloattype{#2}%
+ \ifx\temp\floatmagic
+}
+
+% @listoffloats FLOATTYPE - print a list of floats like a table of contents.
+%
+\parseargdef\listoffloats{%
+ \def\floattype{#1}% floattype
+ {%
+ % the floattype might have accents or other special characters,
+ % but we need to use it in a control sequence name.
+ \indexnofonts
+ \turnoffactive
+ \xdef\safefloattype{\floattype}%
+ }%
+ %
+ % \xrdef saves the floats as a \do-list in \floatlistSAFEFLOATTYPE.
+ \expandafter\ifx\csname floatlist\safefloattype\endcsname \relax
+ \ifhavexrefs
+ % if the user said @listoffloats foo but never @float foo.
+ \message{\linenumber No `\safefloattype' floats to list.}%
+ \fi
+ \else
+ \begingroup
+ \leftskip=\tocindent % indent these entries like a toc
+ \let\do=\listoffloatsdo
+ \csname floatlist\safefloattype\endcsname
+ \endgroup
+ \fi
+}
+
+% This is called on each entry in a list of floats. We're passed the
+% xref label, in the form LABEL-title, which is how we save it in the
+% aux file. We strip off the -title and look up \XRLABEL-lof, which
+% has the text we're supposed to typeset here.
+%
+% Figures without xref labels will not be included in the list (since
+% they won't appear in the aux file).
+%
+\def\listoffloatsdo#1{\listoffloatsdoentry#1\finish}
+\def\listoffloatsdoentry#1-title\finish{{%
+ % Can't fully expand XR#1-lof because it can contain anything. Just
+ % pass the control sequence. On the other hand, XR#1-pg is just the
+ % page number, and we want to fully expand that so we can get a link
+ % in pdf output.
+ \toksA = \expandafter{\csname XR#1-lof\endcsname}%
+ %
+ % use the same \entry macro we use to generate the TOC and index.
+ \edef\writeentry{\noexpand\entry{\the\toksA}{\csname XR#1-pg\endcsname}}%
+ \writeentry
+}}
+